<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

<style>
    
    div {
        width: 100px;
        height: 100px;
        background-color: red;
    }

    span {
        background-color: salmon;
        width: 200px;
    }
    


    .aaa {
        width: 200px;
        height: 100px;
        background-color: red;
    }


</style>

</head>
<body>

    <div>这是一个块</div>
    <div>又是一个快</div>
    <span>这是一个内联</span>
    
</body>
</html>